Detective Sullivan and his team in Maine, join forces with Detective Tweed and his team in Minnesota, when murders begin happening in both states with the same MO. Each murder victim has a chalk line drawn around their lifeless body.

People are being murdered. The police have very few clues and are running into dead ends trying solve the crimes.

The chalk lines appear messy and unsophisticated... until... it becomes clear that the chalk lines are not messy after all... they are messages. The police have to follow the clues and work fast to catch the killer before another victim dies.